Why is AWS expensive? What’s the most costly?

Why vercel? I’ve heard it gets costly at scale here on HN no other data points.

Does the charity have the ability to operate it? Budget? Skills? If not what the plan?

If you want more oomph than that, you can find dedicated server offers at those three places, starting around maybe $30/month. Typically pretty old systems, but I enjoy having a whole ancient box rather than one core in a vm on a modern box. My personal hosting needs are tiny though, so I could fit back into the VPS if money were an issue.

There is also the Techsoup organization, which helps nonprofits and charities with technology needs: https://page.techsoup.org/amazon-web-services-for-nonprofits

I would highly recommend looking through there for not just AWS specific tools & services, but a wide variety of solutions that might help this charity.

Please feel free to reach out directly to me for additional assistance. Hope this helps!

Most of AWS services exist because people are either too lazy or not knowledgeable enough on how to set up their own stuff on EC2.

However, cheap used mini PCs from the likes of HP can be had for very little or even free if you find an office that's replacing them with new ones. Plop on of those at home, and your recurring costs are like 20W of power

I host a few sites on fly for pennies, but they don’t see a lot of traffic.

If traffic is high, this could get pricy. For example, i have a site up getting about 20,000k visitors a day, hitting it many times each and it's probably costing me $400/month whereas a $50 server would probably do the trick (it's a temporary thing that i'm migrating away soon). But I have a bunch of smaller projects with a few visitors a day and the cost rounds to $0.

The nice thing is that it'll basically scale infinitely when you need it to.